Indian Prime Minister Narendra Modi's closest political associate has been named the president of his ruling Bharatiya Janata Party (BJP) as the leader tightened his grip on the party he carried to its biggest election victory in May.

"The spectacular success that he achieved in Uttar Pradesh has never been done before," the outgoing party chief, Rajnath Singh, told a news conference on Wednesday. "So we decided to give him the national responsibility."

Amit Shah is a controversial former minister from Modi's home state of Gujarat in western India. He faces three counts of murder and was banned briefly during the election campaign this year for delivering hate speeches.

The party's top decision-making parliamentary board unanimously chose Shah as his successor, added Rajnath Singh, who is now in government as the federal home minister.

As workers at party headquarters celebrated with the beating of drums, Singh and Modi both offered sweets to Shah.

Sad day?

Modi posted a message on Twitter saying Shah had started his journey as a simple party worker and repeatedly proved himself.

But Shah's elevation as head of a major party marked a new low, said Yogendra Yadav, a leader of the Aam Aadmi Party, which has campaigned for a clean-up of Indian politics.

"A sad day," Yadav said in a Twitter message. "Amit Shah's appointment as BJP president further lowers the minimum moral qualification for becoming a national leader."

The son of a well-to-do businessman, Shah was interior minister for seven years in Modi's cabinet in Gujarat before his 2010 arrest on murder charges and subsequent release on bail.

Shah denies charges that he ordered the killing of a man who the police said was on a mission to assassinate Modi. The man's wife and a witness were also killed.

Critics say the BJP, which is the political offspring of the Hindu nationalist Rashtriya Swayamsevak Sangh, has a deep-seated bias against India's 160 million Muslims. The party denies the charge and says it is opposed to the appeasement of any group.

Source: Agencies